The present invention relates to a cleaning apparatus and a cleaning method, by which objects to be processed, such as semiconductor wafers and glass substrates for a LCD (liquid crystal display) unit etc., are immersed and cleaned in chemical and subsequently dried.
For example, in a cleaning treatment of a manufacturing process for a semiconductor device, such as LSI etc., various cleaning apparatuses are employed for removing contaminants on the surfaces of the semiconductor wafers, such as particles, organic contaminants, metallic impurities and so on, and for etching the surface of the wafer. Note, in this specification, the semiconductor wafer(s) will be called the wafer(s) for short, hereinafter. Above all, a cleaning apparatus of xe2x80x9cwetxe2x80x9d type comes into wide use on the grounds that the above contaminants can be removed effectively, etching can be done and a batch processing can be accomplished to enhance the throughput in the cleaning process.
In such a wet type of cleaning apparatus, the wafers to be cleaned are subjected to a chemical cleaning process (e.g. ammonia treatment, hydrogen fluoride treatment, sulfuric acid treatment etc.) a washing cleaning process using pure water etc., and a drying process using isopropyl alcohol [(CH3)2CHOH] or the like. Note, the isopropyl alcohol will be referred the IPA, hereinafter. Further, the cleaning apparatus is so constructed to supply the chemicals, the pure water and the IPA to processing baths in processing order and a drying room, respectively. Thus, with the above arrangement, a batch processing method where the wafers in blocks of e.g. 50 sheets are successively immersed in the processing baths and dried in the drying room, comes into wide use.
However, the provision of the processing baths and the drying room for each process causes the apparatus to be large-sized undesirably. In addition, because of a lot of opportunities for transporting the wafers in the apparatus, in other words, being exposed to atmosphere, there is a great possibility of the particles"" sticking to the wafers.
Therefore, in e.g. Japanese Unexamined Patent Publication (kokai) No. 64-81230 and the same No. 6-326073 etc., there are proposed cleaning apparatuses in each of which the processing baths and. the drying room are formed in one body, so that the above-mentioned chemical process and drying process are carried out in one chamber. FIG. 1 shows one example of the cleaning apparatuses in the publications, representatively.
The shown cleaning apparatus comprises a chamber 200 and chemical (liquid) 202 stored in a lower portion 201 of the chamber 200. In processing, a wafer W is firstly immersed in the chemical 202. Thereafter, the wafer W is pulled up from the chemical 202 and then subjected to the drying process using the IPA etc. at an upper portion 203 of the chamber 200.
In the above-mentioned drying process while heating, however, there is a possibility that chemical atmosphere remaining in an upper area of the chamber 200 exerts a bad influence on the wafer W during the drying process. Furthermore, since there is a need to meet respective requirements of the chemical and drying processes simultaneously, the degree of freedom is restricted in design of the cleaning apparatus. Therefore, it is difficult to adopt various ideas to realize a high-speed cleaning process, a miniaturization of the chamber and so on.
Accordingly, it is therefore an object of the present invention to provide a cleaning apparatus and a cleaning method, by which a object to be processed is not subjected to a bad influence from the chemical process during the drying process.
It is the other object of the present invention to provide a cleaning apparatus which has a high degree of freedom in design thereby to clean the objects rapidly and miniaturize the apparatus itself, and a cleaning method realized by using the cleaning apparatus.
It is the other object of the present invention to provide a cleaning apparatus and a cleaning method, by which it is possible to execute the drying process more effectively.
It is the other object of the present invention to provide a cleaning apparatus which is capable of preventing surfaces of the objects from being oxidized.
It is the other object of the present invention to provide a cleaning apparatus in which a processing bath and a drying section are separated from each other thereby to prevent mist etc. of treatment liquids from entering into a drying chamber thereby to accomplish a stable drying performance of the apparatus, and a cleaning method realized by using the cleaning apparatus.
As a first feature of the present invention, the above-mentioned objects described above can be accomplished by a cleaning apparatus comprising:
a processing bath for storing processing liquid in which the object is immersed;
a drying chamber arranged above the processing bath and provided with an opening which is disposed between a body of the drying chamber and the processing bath and through which the object is transported, the opening being capable of closing;
transporting means for transporting the object between the processing bath and the drying chamber through the opening; and
first blowing means arranged in the drying chamber, for blowing gas containing inert gas against the object.
Further, a second feature of the present invention resides in the cleaning apparatus in accordance with the first feature, further comprising second blowing means arranged between the processing bath and the drying chamber, for blowing the gas containing the inert gas against the object transported from the processing bath to the drying chamber.
A third feature of the present invention resides in the cleaning apparatus in accordance with the first feature, further comprising
heating means arranged in the drying chamber, for heating the object.
A fourth feature of the present invention resides in the cleaning apparatus in accordance with the first feature, wherein the first blowing means blows the gas containing the inert gas over said object from an upper section of the drying chamber in a downward flowing manner; and further including:
discharging means for discharging the gas blown out from the first blowing means from a lower section of the drying chamber;
wherein the discharging means includes an exhaust port through which the gas is discharged from the drying chamber.
A fifth feature of the present invention resides in the cleaning apparatus in accordance with the fourth feature, further comprising rectifying means for communicating with the exhaust port and having a plurality of intake ports for introducing the gas containing the inert gas, which has been blown out from the first blowing means, through a lower section of the drying chamber.
A sixth feature of the present invention resides in the cleaning apparatus in accordance with the first or second feature, wherein the inert gas is nitrogen gas.
A seventh feature of the present invention resides in the cleaning apparatus in accordance with the first or second feature, wherein the inert gas is heated inert gas.
An eighth feature of the present invention resides in the cleaning apparatus in accordance with the sixth feature, wherein the gas containing the inert gas is a mixed gas composed of an organic solvent and inert gas.
A ninth feature of the present invention resides in the cleaning apparatus in accordance with the sixth feature, wherein the gas containing the inert gas is a mixed gas composed of an organic solvent and heated inert gas.
A tenth feature of the present invention resides in the cleaning apparatus in accordance with the first feature, wherein the processing liquid stored in the processing bath is a deaerated rinse.
An eleventh feature of the present invention resides in a cleaning method of cleaning a object to be processed, the cleaning method comprising the steps of:
(a) immersing the object into a processing bath for storing processing liquid;
(b) transporting the object from the processing bath to a drying chamber arranged above the processing bath through an opening which is capable of opening and closing;
(c) closing the opening after the object has been transported to the drying chamber; and
(d) blowing gas containing inert gas against the object;
A twelfth feature of the present invention resides in a cleaning method of cleaning a object to be processed, the cleaning method comprising the steps of:
(a) immersing the object into a processing bath for storing processing liquid;
(b) transporting the object from the processing bath to a drying chamber arranged above the processing bath through an opening which is capable of opening and closing;
(c) blowing gas containing inert gas against the object; and
(d) closing the opening.
A thirteenth feature of the present invention resides in the cleaning method in accordance with the eleventh or twelfth feature, wherein, prior to the step of (b), the drying chamber has been filled up with an atmosphere of an organic solvent.
According to the first feature of the invention, since the drying chamber and the processing bath are separated from each other up and down while a space of the drying chamber can be insulated from a space of the processing bath through the closing opening, the object has no possibility to receive a bad influenced from the chemical treatment during the drying process. In addition, since the arrangement allows the drying chamber and the processing bath to be designed under respective conditions independent of each other, it is possible to optimize the cleaning process and further miniaturize the cleaning apparatus because of the enhanced degree of freedom in the process design. Moreover, since the cleaning apparatus is constructed so as to blow off the processing liquid on the surface of the object by blowing the gas containing the cooled inert gas, it impossible to carry out the drying process more effectively. In addition, since the space for drying the object to be processed is defined apart from the space for the processing bath, it is possible to decrease the former space as possible, thereby realizing the effective drying process.
According to the second feature of the invention, since the second blowing means, which blows the gas containing cooled inert gas against the object on transportation from the processing bath to the drying chamber, serves to assist the drying process for the object, the drying process can be carried out more effectively.
According to the third feature of the invention, since the temperature of the drying chamber can be raised by the heating means, it is possible to execute the drying process more effectively.
According to the fourth feature of the invention, since the gas containing the inert gas flowing downward allows the processing liquid to be blown off the surface of the object, it is also possible to carry out the drying process more effectively.
According to the fifth feature of the invention, since the rectifying means allows the gas containing the inert gas flowing downward to flow against the object uniformly, it is possible to carry out the drying process more effectively.
According to the sixth feature of the invention, owing to using of the nitrogen gas as the inert gas, if the object to be processed is made of silicon element, it is possible to prevent the surface of the object from being oxidized. Further, according to the seventh to ninth features, it is possible to carry out the drying process more effectively.
According to the tenth feature of the invention, since the processing liquid stored in the processing bath is the deaerated rinse, it is possible to prevent the surface of the object from being oxidized in case of the object made of silicon element.
According to the eleventh and twelfth features of the invention, after the object has been transported from the processing bath to the drying chamber, the opening is then closed to shelter the space and thereafter, the object is subjected to the drying process. Thus, the object has no possibility to receive a bad influenced from the chemical treatment during the drying process. Further, since the forthcoming process in the next processing bath can be prepared while the drying process is executed, it is possible to improve throughput of the cleaning apparatus. Additionally, since the arrangement allows the drying chamber and the processing bath to be designed under respective conditions independent of each other, it is possible to optimize the cleaning process and further miniaturize the cleaning apparatus because of the enhanced degree of freedom in the process design. Moreover, since the cleaning apparatus is constructed so as to blow off the processing liquid on the surface of the object by blowing the gas containing the inert gas, it is possible to carry out the drying process more effectively. In addition, since the space for drying the object to be processed is defined apart from the space for the processing bath, it is possible to decrease the former space as possible, thereby realizing the effective drying process.
According to the thirteenth feature of the invention, since the drying chamber has been already fulfilled up with the atmosphere of the organic solvent before the object is transported to the drying chamber, it is possible to execute the drying process more effectively.
The above and other features and advantages of this invention will become apparent, and the invention itself will best be understood, from a study of the following description and appended claims, with reference had to the attached drawings showing a preferred embodiment of the invention.